The present invention generally relates to a device with at least one support arm.
Concrete spreader columns made up of column arms that are linked together by means of articulated joints and, with a view to saving space, are capable of being folded and subsequently being swung out or extended for operating purposes and make use, especially for the lowest extension and/or support arm or arms, of relatively large differential hydraulic cylinders. These cylinders are employed as a drive for the lifting, lowering and, where appropriate, for the telescoping of an extension arm. The hydraulic cylinders used for this purpose have stroke lengths of up to 2.5 m and over. It is practically self-evident that these hydraulic cylinders have to be designed sufficiently large and dimensionally stable to render them capable of coping with the forces that come into play when the whole of the column is operated. More particularly, when extending and/or moving the arms. Such multi-linked column structures involve considerable weight.
In order to reduce this weight, particular attention must be paid to minimizing the masses that have to be moved, not least, by means of the lowest hydraulic cylinder. It is therefore desirable for extension arms of this type to be made as light as possible while still being able to cope with these large forces during operation.
It is thus the task of the invention to further develop a device of the described kind in such a manner as to render possible, given skillful design, a reduction of the weight of the device via the differential hydraulic cylinders that are to be used as drives for the extension arms, or support arms, of multi-linked crane-shaped extension arms, concrete spreader columns and the like. It is thus designed with a view to saving weight.